JP3889482B2 - Epoxy resin composition and cured product thereof - Google Patents

Description

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【表２】

【００３４】
【発明の効果】
本発明のエポキシ樹脂組成物は、低吸湿性、高耐熱性及び異種材料との高密着性等に優れた硬化物を与え、電子部品封止材として好適に使用することが可能である。
【図面の簡単な説明】
【図１】 図１は、参考例１で合成した芳香族オリゴマーの赤外線吸収スペクトルを示す。[0001]
BACKGROUND OF THE INVENTION
INDUSTRIAL APPLICABILITY The present invention is useful for sealing electrical and electronic parts, circuit board materials, etc. that give a cured product excellent in low hygroscopicity, high heat resistance, and high adhesion to different materials and excellent in electrical insulation. The present invention relates to an epoxy resin composition.
[0002]
[Prior art]
Conventionally, epoxy resins have been used in a wide range of industrial applications, but their required performance has become increasingly sophisticated in recent years. For example, there is a semiconductor sealing material in a typical field of a resin composition mainly composed of an epoxy resin, but as the integration degree of semiconductor elements is improved, the package size is becoming larger and thinner, and the mounting method is also increased. The transition to surface mounting is progressing, and the development of materials with excellent solder heat resistance is desired. Therefore, as a sealing material, in addition to reducing moisture absorption, improvement in adhesion and adhesion at the interface between different materials such as lead frames and chips is strongly demanded.
[0003]
In order to overcome these problems, epoxy resins having various new structures have been studied from the side of the epoxy resin that is the main agent. However, it has been difficult to achieve a balance of physical properties, such as a decrease in heat resistance due to low moisture absorption and a decrease in curability associated with improved adhesion, only by improving the main agent.
[0004]
From such a background, an epoxy resin modifier has been studied. As an example, indene coumarone resin has been conventionally known, and JP-A-1-249824 discloses that coumarone / indene / styrene copolymer resin is applied to a semiconductor sealing material. Aromatic oligomers of the above are inferior in electrical insulation due to insufficient purification of the resin raw material or insufficient removal of the catalyst used for cationic polymerization, especially when used as a semiconductor encapsulant. In addition, there is a problem that the reliability of the indene component is reduced, and the content of the indene component that contributes to improving the adhesion is not sufficient. Japanese Patent Application Laid-Open No. 6-107905 discloses that an indene resin having an increased indene content is applied to an electronic material, but any oligomer having a high indene content has a high softening point. When applied to a semiconductor encapsulant, there is a problem that it is difficult to increase the filling of the filler and the fluidity during molding is lowered.
[0005]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide an epoxy resin composition that provides a cured product that is excellent in moldability and that has low moisture absorption, high heat resistance, and high adhesion to different materials, and the cured product. is there.
[0006]
[Means for Solving the Problems]
That is, the present invention relates to an epoxy resin composition comprising an epoxy resin, a curing agent and a modifier as essential components, and as the modifier, indene and styrene having a content of alkali metal ions and halogen ions of 20 ppm or less. obtained a monomer composed mainly by cationic polymerization, and an infrared absorption spectrum 1480cm around indene ^-1 C = C stretching of the absorbance a and 700 cm ^-1 vicinity of styrene vibration C-H bending vibration Absorbance b ratio (a / b) is 1.08 or more, softening point is 60 to 110 ° C., melt viscosity at 150 ° C. is 2 to 30 poise, and the total of indene component and styrene component is 80% by weight or more. An epoxy resin composition comprising 5 to 50 parts by weight of an aromatic oligomer based on 100 parts by weight of an epoxy resin. Moreover, this invention is an epoxy resin hardened | cured material formed by hardening | curing this epoxy resin composition.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The epoxy resin composition of the present invention contains an epoxy resin, a curing agent and a modifier as essential components, and uses an aromatic oligomer having an indene component and a styrene component as the modifier.
[0008]
The aromatic oligomer used as a modifier in the present invention is obtained by cationic polymerization of monomers mainly composed of indene and styrene. The excellent adhesion and moisture resistance, which are the effects of the present invention, largely depend on the content of the indene component and the styrene component in the oligomer, particularly the content of the indene component. From the viewpoint of balance of physical properties, the ratio of the indene component The higher the better. As its constituent components, an indene component and a styrene component are contained in an amount of 80% by weight or more, and among them, an indene component is contained as a main component, and C = C of indene near 1480 cm ^{−1 in} infrared absorption spectrum measurement. The ratio (a / b) of the absorbance a of stretching vibration and the absorbance b of CH deformation vibration of styrene around 700 cm ⁻¹ is 0.8 or more.
[0009]
As aromatic oligomers with high indene content, those with a unique ring closure structure of indene structure, high softening point and high viscosity are conventionally known, but when applied to epoxy resin compositions, fluidity during molding There was a problem that decreased. The softening point of the aromatic oligomer used in the present invention is 60 to 110 ° C, preferably 80 to 105 ° C. Further, the melt viscosity at 150 ° C. is 2 to 30 poise, preferably 2 to 20 poise. If the softening point is lower than this, there is a problem that the glass transition point of the cured product is lowered, and if the viscosity is high, it becomes difficult to increase the filler when applied to a semiconductor encapsulant and the flow during molding Sex is reduced. The molecular weight of the aromatic oligomer used in the present invention is about 200 to 3000 in terms of number average molecular weight.
[0010]
The aromatic oligomer used in the present invention is preferably a high-purity one having a small content of ionic components. In particular, alkali metal ions such as sodium and potassium, and those containing less halogen ions such as chlorine ions and bromine ions are preferable, and the content of alkali metal ions and halogen ions is 20 ppm or less, preferably 10 ppm or less, more preferably 5 ppm or less. is there.
[0011]
The aromatic oligomer used in the present invention is obtained by cationic polymerization of a monomer containing indene and styrene. Monomers used with indene and styrene include, for example, methylindenes, benzothiophene, methylbenzothiophenes, benzofuran, methylbenzofurans, alkylstyrenes, α-methylstyrene, vinylnaphthalene, vinylbiphenyl, acenaphthylene, acrylic acid, acrylic Examples thereof include monomers having an unsaturated bond such as acid esters, methacrylic acid, methacrylic acid esters, maleic anhydride, fumaric acid, divinylbenzenes, and diisopropenylbenzene. These monomers can use 1 type (s) or 2 or more types, and the compounding quantity is less than 20 weight%.
[0012]
In addition, phenols can be used to modify the end of the aromatic oligomer to improve compatibility with the epoxy resin. Examples of the phenols include alkylphenols such as phenol and cresol, dialkylphenols such as xylenol, bisphenols such as naphthols, bisphenol A and bisphenol F, or polyfunctional phenol compounds such as phenol novolac and phenol aralkyl resin. Etc. The blending amount of these phenol compounds is less than 20% by weight. If it is more than this, the heat resistance and moisture resistance of the cured epoxy resin will be lowered.
[0013]
As a raw material for the polymerization of the aromatic oligomer used in the present invention, styrene or other components may be blended with high purity indene, but 130 to 200 ° C. obtained by distillation of coal tar or coke oven gas gas oil. It is also possible to use a raw material oil containing indene obtained by distilling a raw material oil mainly composed of a fraction or an aromatic oil produced during petroleum refining or petroleum decomposition. On the other hand, petroleum-based or coal-based raw materials contain bases typified by pyridines and quinolines and aromatic carboxylic acids and have a problem of causing polymerization inhibition. In order to remove bases and acids, pickling with sulfuric acid, etc., and alkaline washing with caustic soda, etc. are carried out, which causes sulfate ions, sodium ions, etc. to be mixed into the raw materials, and the resulting aromatic oligomer electricity. There is a problem that the conductivity is increased. Accordingly, it is preferable to use a raw material for polymerization that has been sufficiently washed, or one that has been further distilled by pickling and alkali washing to remove ionic components.
[0014]
The aromatic oligomer used in the present invention is usually synthesized by cationic polymerization in the presence of an acidic catalyst. The acidic catalyst can be appropriately selected from known inorganic acids and organic acids. For example, mineral acids such as hydrochloric acid, sulfuric acid and phosphoric acid, formic acid, oxalic acid, trifluoroacetic acid, p-toluenesulfonic acid, methane Examples thereof include organic acids such as sulfonic acid, Lewis acids such as zinc chloride, aluminum chloride, iron chloride, and boron trifluoride, and solid acids such as activated clay, silica alumina, and zeolite.
[0015]
This cationic polymerization is usually performed at 10 to 250 ° C. for 1 to 20 hours. In the reaction, for example, alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol, methyl cellosolve, ethyl cellosolve, aromatic compounds such as benzene, toluene, chlorobenzene, dichlorobenzene, etc. should be used as a solvent. Can do.
[0016]
The compounding quantity of the aromatic oligomer used for this invention is 2-50 weight part normally with respect to 100 weight part of epoxy resins, Preferably it is 5-30 weight part. If it is less than this, the effect of improving low hygroscopicity and adhesion is small, and if it is more than this, there is a problem that the strength and heat resistance of the cured product are lowered.
[0017]
The epoxy resin used in the epoxy resin composition of the present invention is selected from those having two or more epoxy groups in one molecule. Examples of such epoxy resins include divalent phenols such as bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4′-biphenol, 2,2′-biphenol, tetrabromobisphenol A, hydroquinone, and resorcin. And novolak resins such as tris- (4-hydroxyphenyl) methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, phenol, cresol, naphthol, aralkyl resins such as phenol, cresol, naphthol, etc. Examples thereof include glycidyl etherified compounds of trivalent or higher phenolic compounds. These epoxy resins may be used independently and may use 2 or more types together.
[0018]
As the curing agent used in the epoxy resin composition of the present invention, all those generally known as epoxy resin curing agents can be used, such as dicyandiamide, acid anhydrides, polyhydric phenols, aromatic and aliphatic amines. And the like. Among these, polyhydric phenols are preferably used as a curing agent in a field where high electrical insulation properties such as a semiconductor sealing material are required. These curing agents may be used alone or in combination of two or more.
[0019]
Among these curing agents, acid anhydride curing agents include, for example, phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyl hymic anhydride, and dodecynyl succinic anhydride. Examples include acid, nadic anhydride, and trimellitic anhydride.
[0020]
Examples of polyhydric phenols include divalent phenols such as bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4′-biphenol, 2,2′-biphenol, hydroquinone, resorcin, naphthalenediol, and tris. -Trivalent or higher phenols represented by (4-hydroxyphenyl) methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, phenol novolak, o-cresol novolak, naphthol novolak, polyvinylphenol and the like. And phenols, naphthols or bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4′-biphenol, 2,2′-biphenol, hydroquinone, resorcin, naphthalenediol, etc. Examples thereof include polyhydric phenolic compounds synthesized by a divalent phenol and a condensing agent such as formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, and p-xylylene glycol.
[0021]
Examples of amines include aromatic amines such as 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenylsulfone, m-phenylenediamine, p-xylylenediamine, and ethylenediamine. And aliphatic amines such as hexamethylenediamine, diethylenetriamine, and triethylenetetramine.
[0022]
Moreover, you may mix | blend suitably oligomers or high molecular compounds, such as polyester, polyamide, a polyimide, a polyether, a polyurethane, a petroleum resin, and a phenoxy resin other than the said essential component, in the epoxy resin composition of this invention.
[0023]
Furthermore, the epoxy resin composition of the present invention may contain additives such as inorganic fillers, pigments, flame retardants, thixotropic agents, coupling agents, fluidity improvers and the like. Examples of inorganic fillers include silica powder such as spherical or crushed fused silica and crystalline silica, alumina powder, glass powder, mica, talc, calcium carbonate, alumina, hydrated alumina, etc. Organic or inorganic extender pigments, scaly pigments and the like can be mentioned. Examples of the thixotropic agent include silicon-based, castor oil-based, aliphatic amide wax, oxidized polyethylene wax, and organic bentonite-based.
[0024]
Moreover, conventionally well-known hardening accelerators, for example, amines, imidazoles, organic phosphines, a Lewis acid, etc. can be mix | blended with the epoxy resin composition of this invention as needed. The blending amount is about 0.2 to 5 parts by weight with respect to 100 parts by weight of the epoxy resin. Further, if necessary, the epoxy resin composition of the present invention includes a release agent such as carnauba wax and OP wax, a coupling agent such as γ-glycidoxypropyltrimethoxysilane, a colorant such as carbon black, and the like. A flame retardant such as antimony oxide, a low stress agent such as silicon oil, and a lubricant such as calcium stearate may be blended.
[0025]
When the epoxy resin composition of the present invention is used as a semiconductor sealing material, an inorganic filler such as silica is blended as a main essential component in addition to the epoxy resin, the curing agent and the modifier.
[0026]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.
Reference example 1
70 g of indene, 25 g of styrene and 5 g of phenol were dissolved in 250 g of toluene, heated to 115 ° C., and then 1 g of boron trifluoride dimethyl ether complex was added dropwise over 15 minutes while stirring. After dropping, the reaction was further continued for 3 hours. Thereafter, 2.4 g of calcium hydroxide was added for neutralization. The neutralized salt and excess calcium hydroxide were removed by filtration, and further, washing with 100 ml of ion-exchanged water was repeated three times, followed by distillation under reduced pressure to remove toluene and unreacted monomers to obtain 89 g of aromatic oligomers. The softening point of the obtained resin was 98 ° C., and the melt viscosity at 150 ° C. was 8 poise. The indene / styrene ratio obtained from the infrared absorption spectrum of the obtained resin was 1.08. The indene / styrene ratio was measured as follows. That is, 0.2 g of resin was dissolved in 1 ml of chloroform, this solution was thinly applied to a KBr plate and dried, and an infrared absorption spectrum was measured with an infrared spectrophotometer. Absorption near 1480 cm ⁻¹ (inden It was determined from the ratio of the absorbance of C = C stretching vibration) and the absorbance near 700 cm ⁻¹ (C—H bending vibration of styrene). The infrared absorption spectrum of this resin is shown in FIG.
[0027]
Reference example 2
Reaction was performed in the same manner as in Reference Example 1 using 90 g of indene and 10 g of styrene to obtain 92 g of an aromatic oligomer. The softening point of the obtained resin was 105 ° C., and the melt viscosity at 150 ° C. was 16 poise. The indene / styrene ratio obtained from the infrared absorption spectrum of the obtained resin was 2.1.
[0028]
Reference example 3
Reaction was performed in the same manner as in Reference Example 1 using 50 g of indene and 50 g of styrene to obtain 92 g of an aromatic oligomer. The softening point of the obtained resin was 84 ° C., and the melt viscosity at 150 ° C. was 5 poise. The indene / styrene ratio obtained from the infrared absorption spectrum of the obtained resin was 0.7.
[0029]
Reference example 4
The reaction was performed in the same manner as in Reference Example 1 using 80 g of indene and 20 g of styrene, the reaction temperature being 90 ° C., and 95 g of aromatic oligomer was obtained. The resulting resin had a softening point of 120 ° C. and a melt viscosity at 150 ° C. of 42 poise. The indene / styrene ratio obtained from the infrared absorption spectrum of the obtained resin was 1.8.
[0030]
Examples 1-3 and Comparative Examples 1-3
As the modifier, the aromatic oligomer obtained in Reference Examples 1 and 2 (Modifiers A and B) and the aromatic oligomer obtained in Reference Examples 3 and 4 (Modifiers C and D) were used. As an epoxy resin component, o-cresol novolak epoxy resin (epoxy resin A: Nippon Kayaku Co., Ltd., EOCN-1020-70; epoxy equivalent 200, hydrolyzable chlorine 400 ppm, softening point 70 ° C.), biphenyl epoxy resin (Epoxy resin B: manufactured by Yuka Shell Epoxy Co., Ltd., YX4000HK; epoxy equivalent 195, hydrolyzable chlorine 450 ppm, melting point 105 ° C.), phenol novolac (manufactured by Gunei Chemical Co., Ltd., PSM-4261; OH) as a curing agent Equivalent 103, softening point 82 ° C.) and novolak brominated epoxy (manufactured by Nippon Kayaku Co., Ltd., BREN-S; Epoxy) as a flame retardant Equivalent 284, hydrolyzable chlorine 600 ppm, softening point 84 ° C.), spherical silica (average particle size, 25 μm) as filler, triphenylphosphine as curing accelerator, γ-aminopropyltriethoxysilane as silane coupling agent and others Using the additives shown in Table 1, the epoxy resin composition was prepared by kneading with the formulation shown in Table 1 (the values in the table are parts by weight). The epoxy resin composition was molded at 175 ° C., post-cured at 175 ° C. for 12 hours to obtain a cured product test piece, and then subjected to various physical property measurements shown below. These measurement results are shown in Table 2.
[0031]
The glass transition point was calculated | required on conditions with a temperature increase rate of 10 degree-C / min with the thermomechanical measuring apparatus. The water absorption rate is obtained by molding a disk having a diameter of 50 mm and a thickness of 3 mm using the epoxy resin composition and absorbing moisture for 24 hours and 100 hours under the conditions of 85 ° C. and 85% RH after post-curing. The crack generation rate was determined by molding QFP-80pin (14 × 20 × 2.5 mmt), post-curing, absorbing moisture for a predetermined time under conditions of 85 ° C. and 85% RH, and then dipping in a solder bath at 260 ° C. for 10 seconds. Later, the state of the package was observed and determined. In addition, the evaluation of adhesiveness was carried out by compression-molding the epoxy resin composition at 175 ° C. in a 10 × 10 × 1 mmt mold sandwiched between 42 alloy base materials, followed by post-curing at 175 ° C. for 12 hours and curing. After obtaining an object test piece, the tensile strength was measured.
[0032]
[Table 1]

[0033]
[Table 2]

[0034]
【The invention's effect】
The epoxy resin composition of the present invention gives a cured product excellent in low hygroscopicity, high heat resistance, and high adhesion to different materials, and can be suitably used as an electronic component sealing material.
[Brief description of the drawings]
FIG. 1 shows an infrared absorption spectrum of an aromatic oligomer synthesized in Reference Example 1. FIG.

Claims (2)

In the epoxy resin composition having an epoxy resin, a curing agent and a modifier as essential components, a monomer mainly composed of indene and styrene having a content of alkali metal ions and halogen ions of 20 ppm or less is used as the modifier. obtained by cationic polymerization, and the ratio of the absorbance b of the C-H deformation vibration of styrene near the absorbance a and 700 cm ^-1 of C = C stretching vibration of indene near 1480 cm ^-1 in the infrared absorption spectrum (a An aromatic oligomer having a / b) of 1.08 or more, a softening point of 60 to 110 ° C., a melt viscosity of 2 to 30 poise at 150 ° C., and a total of the indene component and the styrene component of 80% by weight or more, An epoxy resin composition comprising 5 to 50 parts by weight per 100 parts by weight of an epoxy resin. An epoxy resin cured product obtained by curing the epoxy resin composition according to claim 1.

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